I totally agree with pinkmouse, there is more to gain with outboard equipment and proper use than swapping already excellent op-amps.
I went through the same with my Dynacord CMS Mixing Console which comes with Japan Radio (JRC) NJM072 and 5532 op-amps.
All I got from the expensive AD's was higher noise floor and the OPA's sounded "duller" than the stock chips.
There is more involved in such a design as the op-amp alone, I think you'd have to modify the complete circuit.
I went through the same with my Dynacord CMS Mixing Console which comes with Japan Radio (JRC) NJM072 and 5532 op-amps.
All I got from the expensive AD's was higher noise floor and the OPA's sounded "duller" than the stock chips.
There is more involved in such a design as the op-amp alone, I think you'd have to modify the complete circuit.
Good point, I had missed that !
All is not lost however,
http://www.diyaudio.com/forums/parts/127924-working-smd-how-do-without-specialised-tools.html
try and practice on something first, old remote etc
If a mixer were to "colour" the sound at all, I'd never know if what I was doing would translate well on other systems. There is a reason pro gear is designed as neutral as possible, even at the cost of beauty.
But it sounds like you are going to try some mods no matter what....
So, I suggest you start by swapping the opamps on only two channels (maybe the last two) and leave the buss alone for the time being. And only swap out one thing at a time on those channels, then split your well known source into both 1/2 and the modded pair and listen, listen, listen. On the first go, you'll find out if you're onto something that may be better or if you should cease and desist.
At least that's what I would do if I had the hankering to "fix" some pro equipment. Of course, I probably wouldn't for the reasons I started this post with.
BTW, what monitors are you using? I'd wager your biggest problem is the choice of near-fields.
ensen.
But it sounds like you are going to try some mods no matter what....
So, I suggest you start by swapping the opamps on only two channels (maybe the last two) and leave the buss alone for the time being. And only swap out one thing at a time on those channels, then split your well known source into both 1/2 and the modded pair and listen, listen, listen. On the first go, you'll find out if you're onto something that may be better or if you should cease and desist.
At least that's what I would do if I had the hankering to "fix" some pro equipment. Of course, I probably wouldn't for the reasons I started this post with.
BTW, what monitors are you using? I'd wager your biggest problem is the choice of near-fields.
ensen.
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To address some questions... I have the Projectmix, Alesis Micron Synth, Roland Juno-D Keyboard, AKG Perception 100 condensor, KRK Rokit 5s, everything else ITB..ProTools8... am going to purchase the Golden Age 73 preamp (and maybe mod), the Neumann TLM 103, and Behringer SRC2496 (maybe mod) for ad/da. This setup is mainly to record vocals, some guitar and for beat making/sequencing. I was definitely going to start with maybe channel 8 on the board for experimentation and use a socket so I can just drop different chips in. I joined this forum to get expert advice b4 I decided to take a plunge and ruin something. So keep it coming... I am still hesitant to this project... as I don't want to destroy my board.
Wow, so much negativism. I would be nervous about SMD, but not about trying something. First, put a dip socket in for one channel. Then try 5532 vs LM4562 or anything else. 5532 has slew rate of 6 V/usec, LM4562 has 15.Output current is 25 ma which might allow you to decrease feedback resistors and increase feedback capacitors to cut resistor noise. I think it has better noise spec, too, although specmanship may have something to do with it. See this thread about my op amp swap and power supply wars http://www.diyaudio.com/forums/anal...improving-disco-mixer-mid-fi-performance.html Of course I paid $15 for my mixer, and you paid $1200. I had to install better power supply bypassing, and feedback resistor cap bypass to prevent oscillations, but I haven't butchered my PCB yet. I had to suck a few solder bridges off the traces when I installed the sockets, but no other problems. I drilled a few new holes in the PCB to install more bypass caps, using a hand crank MonkeyWards drill for less violence and trash thrown around in my living room. You can also drill holes with a pin vice to keep damage and trash down. You might remove the smd part, then fly a dip socket nearby by drilling holes next to the traces and splicing in a bit of 30 ga wire. This is assuming the PCB is not multi-layer, which has its own dangers.
I did entirely replace the power supply due to the disco mixer stupid mistakes, like a 120 VAC power switch right next to the op amp PCB. But I made a whole different power supply CB out of scrap insulator board with my own holes. Your power supply in a pro mixer might be okay, not causing hum.
These little PCB's from MCM look cute for putting a dip socket on http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-21-110-/21-4575, getting solid core wire in and out securely, and flying it above your SMD socket on a standoff. I've got a can full of 6-32 screws & nuts, but I make the stand offs by cutting up 1/4" nylon air tubing. Use elastic stop nuts, they stay put.
I did entirely replace the power supply due to the disco mixer stupid mistakes, like a 120 VAC power switch right next to the op amp PCB. But I made a whole different power supply CB out of scrap insulator board with my own holes. Your power supply in a pro mixer might be okay, not causing hum.
These little PCB's from MCM look cute for putting a dip socket on http://www.mcmelectronics.com/product/DISTRIBUTED-BY-MCM-21-110-/21-4575, getting solid core wire in and out securely, and flying it above your SMD socket on a standoff. I've got a can full of 6-32 screws & nuts, but I make the stand offs by cutting up 1/4" nylon air tubing. Use elastic stop nuts, they stay put.
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You may also want to leave your pro mixer alone, buy a ****ed out disco mixer for $40, buy new pots and play with the SIP op amps on it to see if you can make it sound better than your pro mixer. All this cap elitism has me wondering. Stacked looking plastic caps are getting real popular in switching power supplies, what do they sound like? Low self inductance probably. Not precise, but you can measure them before you use them.
indianajo... its a great idea to use a cheap piece of gear first, just to test the sound of each opamp. A while back I made a small "$5 preamp" (Bill's Hobby Circuit Library). Guess I could just use that as my test subject to try and hear differences in these chips, although I doubt it would be possible to make it sound better than my mixer. Do you think it is possible to hear differences in these chips with such a simple circuit? (May have to use this schematic instead for dual opamp test board....http://tangentsoft.net/audio/cmoy-tutorial/misc/cmoy-tangent-sch.pdf).
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You might be hard pushed to hear much difference with just one IC slotting it into a chain.
I find the NE5532 the most intriguing. It's claimed that 90 odd percent of all we listen too has been through many of these devices anyway... and as a straightforward amp it's pretty good. When it's used in DA convertors etc then I can tell immediate improvements in using other devices (such as the OPA2604). I came across a very interesting article some while back saying that this could be doen to HF "hash" in digital equipment causing non linearity and odd distortion products in the bipolar input stage of the NE5532
I did some serious listening to this using NE5532's and found it very hard to say for sure whether other were better.
http://www.diyaudio.com/forums/soli...-built-listened-d-selfs-precision-preamp.html
I find the NE5532 the most intriguing. It's claimed that 90 odd percent of all we listen too has been through many of these devices anyway... and as a straightforward amp it's pretty good. When it's used in DA convertors etc then I can tell immediate improvements in using other devices (such as the OPA2604). I came across a very interesting article some while back saying that this could be doen to HF "hash" in digital equipment causing non linearity and odd distortion products in the bipolar input stage of the NE5532
I did some serious listening to this using NE5532's and found it very hard to say for sure whether other were better.
http://www.diyaudio.com/forums/soli...-built-listened-d-selfs-precision-preamp.html
Have you looked at how the power supplies are implemented in your mixer? You might have a lot to gain from making improvements to them and then you won't have ripped up too much turf in the process. Keep the enhancements incremental then you can always go back.
Mooly said:
Sounds very interesting, do you know where you found that article? I'm finding similar - putting some very small chokes (1-5uH) in series with the inputs to my NE5532s definitely makes a difference to the siblance. I definitely think the writer of that article is on to something valuable.
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Funny..Mooly... I was just looking around for some opamp "test" circuit that I could build to give a listen to the many ics. I'm guessing the preamp stage of this mixer is fed directly into the AD/DA (haven't looked at the other pcbs), kinda why I thought this would be a good experiment. Definitely would love to use a test circuit first though.. if I can't hear a difference in a smaller scale test, I assume it wouldn't be much different in the mixer.. right?
haha.. didn't think you would want it right now... funny I am using the mixer on a daily basis so it is actually hooked up, but I can get a photo soon..
Thought I'd mention that the NOISE I am getting is when I turn the pots up around 65% or more (very loud sssss).. turned the pot all the way up earlier with nothing conected to the input (with headphones on) and noticed a clicking loop.. does seem like current noise from the power section probably...
Thought I'd mention that the NOISE I am getting is when I turn the pots up around 65% or more (very loud sssss).. turned the pot all the way up earlier with nothing conected to the input (with headphones on) and noticed a clicking loop.. does seem like current noise from the power section probably...
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Just a few words regarding SMD. In case there is no hot air soldering station around the following technique could be used for SOIC8: bend just a little of tips of a tweezer inside so you can hook the SOIC8 IC body from beneath. Then using ordinary soldering iron with a good big tip so you can heat all 4 legs from one side all together let it heat for a few seconds and just pull that side of IC slightly up so all 4 legs will be off the soldering contacts. Do same from another side. Actually soldering new SMD way easier then desoldering old one. It takes me less then a minute to replace SOIC8 its amazing how modern SMD parts convenient to work with. DIP8 gives me a way more hassle.
Hi speed opamps like AD8066 do not like being mounted via brown dog adapter that will cause oscillation giving "metallic" sounding. In that case decoupling caps needed to be soldered to V+ V- legs of IC. There are many discussion regarding the subject that can be googled easily.
Hi speed opamps like AD8066 do not like being mounted via brown dog adapter that will cause oscillation giving "metallic" sounding. In that case decoupling caps needed to be soldered to V+ V- legs of IC. There are many discussion regarding the subject that can be googled easily.
Had a good search on here (I posted a link to it) but can't seem to find it... if I do I'll post it.
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